A Study on the Correlation Between Structure and Hole Transport in Semi‐Crystalline Regioregular P3HT

Abstract

A correlation between the hole transport and corresponding structural properties of the bulk regioregular poly(3‐hexylthiophene) (rr‐P3HT) is studied as a function of temperature by the time‐of‐flight (TOF) and wide angle X‐ray diffraction (WAXD) techniques. The thermally‐reversible structural evolution along the (100) and (020) directions in a semi‐crystalline rr‐P3HT can be divided into two distinct temperature regions. At T > 120 °C, a large thermal expansion along the π–π stacking direction in the nanocrystals and a deteriorated ordering in the material result in negative slopes of temperature and electric field dependences of hole mobility. The WAXD data suggest that the hole transport is limited by a decrease in the crystallinity and by an increase in the hopping distance along the π‐π stacking direction, while the Gaussian Disorder Model (GDM) with temperature‐independent parameters cannot be applied. At T < 120 °C, the transport‐related structural changes are negligible and the temperature and electric field dependences of hole mobility can be described by the GDM with constant energetic (σ ∼ 120 meV) and positional disorder parameters (Σ ∼ 3.33). These values suggest that the hole transport is limited by the amorphous phase, as commonly seen in disordered polymers. Moreover, a regiorandom P3HT (rra‐P3HT), which shows a temperature‐independent intermolecular distance of ∼15.3Å, provides a route for separate examination of the amorphous phase in rr‐P3HT.

Interfacial Crystallization‐Driven Assembly of Conjugated Polymers/Quantum Dots into Coaxial Hybrid Nanowires: Elucidation of Conjugated Polymer Arrangements by Electron Tomography

“…[54][55][56][57] When the solution-biphase method is used instead of the one-pot addition method, the (100) refl ection peak intensity increased with a narrow width, indicating an increase in crystallinity and crystal size ( t hkl ), which was evaluated by using the Scherrer equation (see Experimental Section). [ 54,58 ] The crystal size was increased by a factor of almost 2 to about 9.15 nm, compared to that of the NWs produced by the one-pot addition method, suggesting that the stacking defects decreased and the intrachain/interchain ordering increased. Therefore, the fabrication and subsequent crystallinity control of pre-assembled CPs-NWs in the solution-state were important, because these parameters control the crystalline order and morphology of the as-cast fi lms, affecting the performance of electro-optical thin fi lm devices.…”

“…The cleaned substrate was transferred in piranha solution and heated for 1 h at 100 °C. The crystal size was measured by the FWHM of the (100) diffraction peak using the Debye-Scherrer equation: [ 54,58,62,63 ] t hkl hkl λ β θ = 0.9 cos (3) where λ is the incident X-ray wavelength, t hkl is the coherent crystal size, K is a dimensionless Scherrer constant (generally given as K = 0.9), β is the FWHM in radians, hkl is the glancing angle. The evaluated crystal sizes along the out-of-plane (100) are given in Table 2 .…”

Reducing burn-in voltage loss in polymer solar cells by increasing the polymer crystallinity

“…34) and regiorandom P3HT is amorphous. 35 Thus, the comparison between (regioregular) P3HT and RRa P3HT is powerful, as they have the same chemistry and differences between these two materials are only caused by their morphology. With PCDTBT and KP115 we compare two high efficiency "donor-acceptor" polymers.…”

Electroactive polythiophene/polystyrene bottlebrushes as morphology compatibilizers in photovoltaic systems

“…The d (100) and d (020) values were 1.054 and 0.301 nm for the P3HT:PC71BM:15 wt% P3ThEt‐ graft ‐PSt systems. In general, via the addition of 15–25 wt% of P3ThEt‐ graft ‐PSt bottlebrushes, the d (100) values ranged from 1.049 to 1.054 nm, which were the minimum d ‐spacings among all our prepared samples, indicating fully interdigitated hexyl chains . The corresponding d (020) values were also the smallest (0.298–0.301 nm).…”